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Author: Javier Montejo Berlingen Publisher: Springer ISBN: 3319410512 Category : Science Languages : en Pages : 288
Book Description
This doctoral thesis focuses on the search for new phenomena in top-antitop quark (tt) final states with additional b-quark jets at the LHC. It uses the full Run 1 dataset collected by the ATLAS experiment in proton-proton collisions at √s=8 TeV. The final state of interest consists of an isolated lepton, a neutrino and at least six jets with at least four b-tagged jets, a challenging experimental signature owing to the large background from tt+heavy-flavor production. This final state is characteristic of ttH production, with the Higgs boson decaying into bb, a process that allows direct probing of the top-Higgs Yukawa coupling. This signature is also present in many extensions of the Standard Model that have been proposed as solutions to the hierarchy problem, such as supersymmetry or composite Higgs models, which predict the pair production of bosonic or fermionic top quark partners, or the anomalous production of four-top-quark events. All these physics processes have been searched for using an ambitious search strategy that has been developed on the basis of a combination of state-of-art theoretical predictions and a sophisticated statistical analysis to constrain in-situ the large background uncertainties. As a result, the most restrictive bounds to date on the above physics processes have been obtained.
Author: Javier Montejo Berlingen Publisher: Springer ISBN: 3319410512 Category : Science Languages : en Pages : 288
Book Description
This doctoral thesis focuses on the search for new phenomena in top-antitop quark (tt) final states with additional b-quark jets at the LHC. It uses the full Run 1 dataset collected by the ATLAS experiment in proton-proton collisions at √s=8 TeV. The final state of interest consists of an isolated lepton, a neutrino and at least six jets with at least four b-tagged jets, a challenging experimental signature owing to the large background from tt+heavy-flavor production. This final state is characteristic of ttH production, with the Higgs boson decaying into bb, a process that allows direct probing of the top-Higgs Yukawa coupling. This signature is also present in many extensions of the Standard Model that have been proposed as solutions to the hierarchy problem, such as supersymmetry or composite Higgs models, which predict the pair production of bosonic or fermionic top quark partners, or the anomalous production of four-top-quark events. All these physics processes have been searched for using an ambitious search strategy that has been developed on the basis of a combination of state-of-art theoretical predictions and a sophisticated statistical analysis to constrain in-situ the large background uncertainties. As a result, the most restrictive bounds to date on the above physics processes have been obtained.
Author: Michail Bachtis Publisher: Springer Science & Business Media ISBN: 3319032577 Category : Science Languages : en Pages : 161
Book Description
The work presented in this thesis spans a wide range of experimental particle physics subjects, starting from level-1 trigger electronics to the final results of the search for Higgs boson decay and to tau lepton pairs. The thesis describes an innovative reconstruction algorithm for tau decays and details how it was instrumental in providing a measurement of Z decay to tau lepton pairs. The reliability of the analysis is fully established by this measurement before the Higgs boson decay to tau lepton pairs is considered. The work described here continues to serve as a model for analysing CMS Higgs to tau leptons measurements.
Author: Martin Lewis Perl Publisher: World Scientific ISBN: 9814553662 Category : Languages : en Pages : 315
Book Description
It has been more than a decade since new elementary particles were discovered. To recognize the findings of scientists in this still fairly new but exciting and promising area of research, the Trieste Workshop was organised in May 1992 to discuss the status and explore the prospects for the discovery of new elementary particles using the full variety of search methods which are, or will be available to the physicist. All papers in this collection of proceedings are reviews written by experts in their own area of speciality. Many review papers based on experimental findings are also included. To present a clearer and more coherent overview, a theoretical overview talk as well as a summary talk have been included to serve as a link between the various areas that were discussed in the papers. This collection of papers is perhaps the first authoritative source ever published on the search for new elementary particles.
Author: Luca Cadamuro Publisher: Springer ISBN: 3030040550 Category : Science Languages : en Pages : 283
Book Description
This thesis presents innovative contributions to the CMS experiment in the new trigger system for the restart of the LHC collisions in Run II, as well as original analysis methods and important results that led to official publications of the Collaboration. The author's novel reconstruction algorithms, deployed on the Field-Programmable Gate Arrays of the new CMS trigger architecture, have brought a gain of over a factor 2 in efficiency for the identification of tau leptons, with a very significant impact on important H boson measurements, such as its decays to tau lepton pairs and the search for H boson pair production. He also describes a novel analysis of HH → bb tautau, a high priority physics topic in a difficult channel. The original strategy, optimisation of event categories, and the control of the background have made the result one of the most sensitive concerning the self-coupling of the Higgs boson among all possible channels at the LHC.
Author: Simone Marzani Publisher: Springer ISBN: 3030157091 Category : Science Languages : en Pages : 210
Book Description
This concise primer reviews the latest developments in the field of jets. Jets are collinear sprays of hadrons produced in very high-energy collisions, e.g. at the LHC or at a future hadron collider. They are essential to and ubiquitous in experimental analyses, making their study crucial. At present LHC energies and beyond, massive particles around the electroweak scale are frequently produced with transverse momenta that are much larger than their mass, i.e., boosted. The decay products of such boosted massive objects tend to occupy only a relatively small and confined area of the detector and are observed as a single jet. Jets hence arise from many different sources and it is important to be able to distinguish the rare events with boosted resonances from the large backgrounds originating from Quantum Chromodynamics (QCD). This requires familiarity with the internal properties of jets, such as their different radiation patterns, a field broadly known as jet substructure. This set of notes begins by providing a phenomenological motivation, explaining why the study of jets and their substructure is of particular importance for the current and future program of the LHC, followed by a brief but insightful introduction to QCD and to hadron-collider phenomenology. The next section introduces jets as complex objects constructed from a sequential recombination algorithm. In this context some experimental aspects are also reviewed. Since jet substructure calculations are multi-scale problems that call for all-order treatments (resummations), the bases of such calculations are discussed for simple jet quantities. With these QCD and jet physics ingredients in hand, readers can then dig into jet substructure itself. Accordingly, these notes first highlight the main concepts behind substructure techniques and introduce a list of the main jet substructure tools that have been used over the past decade. Analytic calculations are then provided for several families of tools, the goal being to identify their key characteristics. In closing, the book provides an overview of LHC searches and measurements where jet substructure techniques are used, reviews the main take-home messages, and outlines future perspectives.
Author: Johanna Gramling Publisher: Springer ISBN: 3319950169 Category : Science Languages : en Pages : 290
Book Description
This book discusses searches for Dark Matter at the CERN’s LHC, the world’s most powerful accelerator. It introduces the relevant theoretical framework and includes an in-depth discussion of the Effective Field Theory approach to Dark Matter production and its validity, as well as an overview of the formalism of Simplified Dark Matter models. Despite overwhelming astrophysical evidence for Dark Matter and numerous experimental efforts to detect it, the nature of Dark Matter still remains a mystery and has become one of the hottest research topics in fundamental physics. Two searches for Dark Matter are presented, performed on data collected with the ATLAS experiment. They analyze missing-energy final states with a jet or with top quarks. The analyses are explained in detail, and the outcomes and their interpretations are discussed, also in view of the precedent analysis of theoretical approaches. Given its depth of coverage, the book represents an excellent reference guide for all physicists interested in understanding the theoretical and experimental considerations relevant to Dark Matter searches at the LHC.
Author: A. I. Studenikin Publisher: World Scientific ISBN: 9812837582 Category : Science Languages : en Pages : 495
Book Description
This proceedings volume is devoted to a wide variety of items, both in theory and experiment, of particle physics such as tests of the Standard Model and beyond, physics at the future accelerators, neutrino and astroparticle physics, heavy quark physics, non-perturbative QCD, quantum gravity effects and cosmology. It is important that the papers in this volume reveal the present status and new developments in the above-mentioned items on the eve of a new era that starts with the Large Hadron Collider (LHC).
Author: Daiki Yamaguchi Publisher: Springer Nature ISBN: 9811509328 Category : Science Languages : en Pages : 288
Book Description
This book reports on the search for a new heavy particle, the Vector-Like Top quark (VLT), in the Large Hadron Collider (LHC) at CERN. The signal process is the pair production of VLT decaying into a Higgs boson and top quark (TT→Ht+X, X=Ht, Wb, Zt). The signal events result in top–antitop quarks final states with additional heavy flavour jets. The book summarises the analysis of the data collected with the ATLAS detector in 2015 and 2016. In order to better differentiate between signals and backgrounds, exclusive taggers of top quark and Higgs boson were developed and optimised for VLT signals. These efforts improved the sensitivity by roughly 30%, compared to the previous analysis. The analysis outcomes yield the strongest constraints on parameter space in various BSM theoretical models. In addition, the book addresses detector operation and the evaluation of tracking performance. These efforts are essential to properly collecting dense events and improving the accuracy of the reconstructed objects that are used for particle identification. As such, they represent a valuable contribution to data analysis in extremely dense environments.
Author: Satoshi Matsuda Publisher: World Scientific ISBN: 9789971505899 Category : Science Languages : en Pages : 458
Book Description
This book is dedicated to Prof H Miyazawa in commemoration of his 60th birthday. He is an outstanding particle physicist who gave an original idea on nuclear magnetic moments and has led the frontier of particle physics. Here is a historical survey featuring the stress on phenomenologies in particle physics. It should be of interest to experimental physicists also.
Author: Javier Montejo Berlingen
Author: Javier Montejo Berlingen
Author: Michail Bachtis
Author: Martin Lewis Perl
Author: Luca Cadamuro
Author: Simone Marzani
Author: Johanna Gramling
Author: A. I. Studenikin
Author: Daiki Yamaguchi
Author: Satoshi Matsuda
Author: